1. Field of Invention
The present invention relates to a mobile device having a robotic arm. More particularly, the present invention relates to a device with a robotic arm to retrieve data from radio frequency identification (RFID) tags.
2. Description of Related Art
A radio frequency identification (RFID) system is an automatic identification system, which relies on radio waves to store and retrieve data remotely. Generally speaking, the RFID system contains an RFID tag (i.e. an electronic tag) and a reader. The RFID tag is an object that can be applied to or incorporated into a product, the body of an animal, or the body of a human for the purposes of identification using radio waves to communicate between the tag and the reader.
Most electronic tags contain at least two parts. One is an integrated circuit for storing and processing information, modulating and demodulating an (RF) signal, and can also be used for other specialized functions. The second is an antenna for receiving and transmitting the signal.
RFID tags are divided into two general varieties: passive or active. Passive tags require no internal power supply. They are worked or operated only when a reader is nearby to power them. Passive tags have an operational reading distance ranging from about 10 cm up to a few meters relative to the reader, depending on the chosen radio frequency and antenna design/size.
Active tags require a power source, usually a small battery. Many active tags today have an operational reading range of hundreds of meters. Active tags typically have much longer distance range (approximately 500 m) than passive tags. However, passive tags are extensively applied to a variety of occasions because of their lower cost. Moreover, a fixed reader could retrieve data of passive tags within the operational reading distances range. However, if many fixed readers are installed to cover the whole range the cost increases.
The operational reading distances of RFID tags are limited by surrounding metal interference and communicational direction limitation so the effective operational reading distance is smaller than the distance in theory, which increases the difficulty to retrieve data.
The purpose of the RFID system is to provide a periodical check of goods, for example to take inventory of goods in a warehouse. In addition to wasting time, manually retrieving RFID data also misses tags easily. Moreover, if the RFID tags are installed too high or too low, the difficulty of retrieving data is increased. The risk will be increased when some goods with RFID tags are placed in dangerous areas (such as high temperature, radiation and so on),